If you want to sell your product to boat builders you need to work in
feet.inches.eighths+/-a sixteenth

This is the way their 'Tables of Offsets' and blue prints are marked.

e.g 1. four feet, seven inches, three eighths and an extra sixteenth is
written as 4.7.3+
e.g 2. two feet, five inches, seven eighths is written as 2.5.7
e.g 3. one foot, three inches, two eighths and a reduction by a sixteenth is
written as 1.3.2-
(The sixteenths are not meant to be actually measured, but are an indication
of which side of a drawn line to cut or join to).

Engineers will want tenths, hundredths and 'mils' (one thousandths of an
inch).

'Craftsmen' will require simple divisions in the series - half, quarter,
eighth, sixteenth, thirty seconds, sixty fourths; with perhaps thirds and
tenths added as well.
Metricated craftsmen will want twenty fifths of an inch (which closely
approximates a millimetre).

I suggest you store the measurements as 1 / 240 of an inch and convert to
the desired system as required. This fractional value will fit in a single
byte and will readily convert to most of the systems in use (except for
mils), including rounding to 2 decimals when a decimal display is desired.
Storing as 1 / 64 is also feasible, but doesn't readily give 1 / 10"   :(

For the parts-of-an-inch display give the user the choice of -
Fractions, displayed as 1 / 2",   3 / 4",   7 / 8",   15 / 16",   31 / 32",
63 / 64"
Decimals, displayed as 3",   3.4",   3.37"
Maritime (inches and eighths), displayed as .4+,   .4,   .4-

Even if you don't offer alternate displays for this project I think it would
be worth while to work in 1 / 240" internally so that the code can be reused
in later projects.

Bye.


        -----Original Message-----
        From:   Quentin [SMTP:qsc@ICON.CO.ZA]
        Sent:   Tuesday, 10 April 2001 22:10
        To:     PICLIST@MITVMA.MIT.EDU
        Subject:        [PIC]: Help the metric man

        I need to measure and count in feet and inches and display it on a
LCD.

        I always worked in metric before where I normally use a register
each
        for fractions, ones, tens, hundreds, etc.
        This is easy to display and manipulate.
        Now I have to do the same for feet and inches. I know there is 12
inches
        in a foot, so that one is not a problem. But what is the general way
of
        displaying fractions of an inch?. Do you just use decimal? I.E.: 1/2
        inch do you show it as 0.5 inch?

        Also feet is indicated by a ' symbol and inch by " symbol. Right?
        How would you show it on and LCD screen?
        Say 5 feet, 10 1/2 inches. Would you do this: 5' 10.5" ?

        I can't see in my minds eye that that will look good on a LCD. But
maybe
        it is because I am not used to looking at it that way.

        The predominant count has to be in feet, so I can't just use inches
as a
        measurement on it's own.

        Any tips on this?
        Thanks
        Quentin

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